As shown in FIG. 1, a conventional plate clamp is composed of a tube insertion hole 1 through which a tube 2 is inserted, a slit section 4 in which the tube 2 is clamped, and a tube lead-in section 3. The tube 2 located in the tube insertion hole 1 is slid to the slit section 4 to clamp the tube 2. However, depending on a tube material or size, the tube 2 may be deformed into a U shape as shown in FIG. 2, thus increasing slide resistance to make the sliding difficult. Furthermore, repeated sliding may cause the tube 2 to be worn away to reduce the strength of the tube 2. Coating of an inner surface of the clamp with a lubricant has been proposed to solve the above-described problems (Patent Document 2). However, although the lubricant coating the clamp is effective for reducing the slide resistance during clamping, the sliding resistance in the area from the slit section to the insertion hole also decreases to increase the risk of an accident in which the clamp slips unintentionally out of the slit section.
Patent Document 1: Japanese Utility Model Laid-Open No. 63-1541
Patent Document 2: Japanese Patent No. 3517284